The development of hypersensitivity of the CNS following prior exposure to central depressant drugs has important implications in the proper clinical management of CNS disorders. Drug interactions may result due to the hypersensitivity producing overdosage complications. This proposal contains pilot studies to characterize the relationships between the dosage of CNS depressants and the time course of development of the hypersensitivity. The characteristics of the hypersensitivity will be determined through sleeping-time onset and duration, blood and brain drug concentrations and the depression of body temperature control mechanism.